CHICKWEED FAMILY 271 



17. A. calycantha (Bong.) Rydb. Stems numerous, decumbent, more or 

 less pubescent; leaves ovate-lanceolate, ciliolate at least at the base, 5-15 mm. 

 long; sepals lanceolate, acute, about equalling the rounded-ovoid or subspheric, 

 obtuse capsule. S. calycantha Bong. Wet places in the mountains: Mont. — ■ 

 Colo.— Calif.^Alaska. Mont.— Alp. Jl-S. 



18. A. washingtoniana (B. L. Robins.) Heller. Delicate annual (?); stems 

 decumbent, quite simple, more or less pubescent; leaf-blades ovate, acute, short- 

 petioled, thin, 8-10 mm. long, finely ciliate near the base; peduncles spreading; 

 sepals four, ovate, acute, 2-3 mm. long, slightly scarious-margined; petals none; 

 capsule ovoid. S. washingtoniana B. L. Robins. Woods and dry ground : Wash. 

 — Ida. Subiuont. — Mont. Jl-Au. 



19. A. Palmeri Rydb. Stems spreading, 5 cm. high or less, glabrous; leaves 

 ovate or ovate-lanceolate, 2-5 mm. long, fleshy, acute; cyme 3-5-flowered; 

 sepals lanceolate, 2.5-3 mm. long, acute; petals about equalling the sepals. 

 Valleys: s Utah. Son. 



20. A. polygonoides Greene. Stem diffuse, 3-10 cm. long; leaves thick, 

 ovate, 6-12 mm. long; cymes several-flowered, with short branches and pedicels; 

 sepals narrowly lanceolate, slightly scarious-margined, 4 mm. long, acute, nearly 

 twice as long as the petals. High mountains: Colo. — Utah. Subalp. Jl-Au. 



21. A. Curtisii Rydb. Stem sharply 4-angled, erect, branched, 2-6 dm. 

 high, glabrous, except in the inflorescence; leaves rounded and half clasping at 

 the base, 3-6 cm. long; sepals about 3 mm. long, thick, ovate-oblong, obtuse or 

 acutish, with a narrow white margin; petals about 7 mm. long. Open woods: 

 W^yo. — Colo. — Ariz. — Nev. Submont. — Mont. Je-Au. 



22. A, Jamesiana (Torr.) Heller. Stem strongly angled, 2-5 dm. high, 

 viscid above; leaves elongate-lanceolate, 5-12 cm. long, broadest near the base; 

 inflorescence leafy; sepals oblong or elliptic, thin, 4-5 mm. long; petals 7-8 

 mm. long. S. Jamesiana Torr. Moist woodlands: Wyo. — ^Tex. — ^Calif. — Ida. 

 Submont. — -Mont. My-Au. 



23. A. americana (Porter) Rydb. Stems branched, very leafy, 1-2 dm. 

 high, viscid-puberulent; leaves sessile, ovate, obtusish, 1-3 cm. long; cymes 

 very leafy; pedicels short; sepals ovate, obtuse, 3-4 mm. long; petals about 6 

 mm. long. »S'. dichotoma americana Porter. Rock slides: Mont. Subalp. Je- 

 Au. 



2. CERASTIUM L. Mouse-ear Chickweed. 



Annual or perennial herbs, with pubescent, often viscid foliage. Leaves 

 opposite. Flowers cymose. Sepals 5, rarely 4. Petals as many, white, 2-cleft. 

 Stamens usually 10. Ovary one-celled; styles as many as the sepals and ojjposite 

 them, rarely fewer. Capsule cj'lindric, often curved, opening by 10, rarely 

 8, tooth-like valves. 



Annuals; pod 2-3 times as long as the calyx. 



Pedicels in fruit 1-3 times as long as the calyx, straight or nearly so. 



1. C. brachypodum. 

 Pedicels in fruit 5 times as long as the calyx or longer; strongly curved above. 



2. C. nutans. 

 Perennials or rarely annuals; pods 1-2 times as long as the calyx. 



Leaves oblong, oval, or ovate, mostly obtuse, or barely acutish. 

 Petals 1 cm. long or more, fully twice as long as tlie sepals. 



Sepals, at least the outer ones, oval, obtuse, scarious-margined at the tip as 



well as on the sides. 3. P. pulchellum. 



Sepals lanceolate, acute, scarious mostly on the margins only. 

 Leaves and stem distinctly, although not copiously villous. 



4. C. alpinum. 

 Leaves and stem finely pilose. 5. C. Earlei. 



Petals less than 1 cm. long. 



Petals much exceeding tlie sepals. 



Leaves thick with a prominent midrib. 



Plant tall, 4-5 dm. high; leaves linear-oblong. 12. C. Leibergii. 



Plant low, depressed, less than 1 dm. high; leaves ovate-lanceolate. 



18. C. thermale. 

 Leaves thin; midrib not prominent. 



Sepals tinged with purple; stem depressed, 1-3-flowered. 



6. C. Beeringianum. 



